Two of the bigger names in cloud computing -- VMware and Rackspace -- have each released today low-cost or free trial versions of their cloud offerings.

Two of the bigger names in cloud computing -- VMware and Rackspace -- have each released today low-cost or free trial versions of their cloud offerings.

The news follows an announcement by Red Hat earlier this week that it too would offer a free version of its cloud computing platform. Red Hat's and Rackspace's offerings help users build private clouds based on the OpenStack software code, while VMware is offering a free trial version of its vCloud software, which allows access to public cloud resources.

The moves signal an effort by cloud service providers to entice businesses that may have virtualized environments to expand to a public or private cloud, one analyst says.

VMware officials say they are hoping to lower the adoption barrier for its customers who are interested in expanding from an on-premise virtualized environment powered by VMware to a public cloud service offered by one of the more than 150 VMware-certified public cloud vendors. Through the swipe of a credit card on the vCloud portal at VMware.com, customers can launch a vCloud Service Evaluation, public cloud instance of Linux virtual machines that are hosted by a vCloud service provider that the company does not disclose. VMware announced the service today and it will be available in the coming weeks, says Joe Andrews, director of product marketing for vCloud Services. The VMs cost $0.04 per hour per gigabyte of memory.

VMware has not had this "instant gratification," says Gartner cloud analyst Lydia Leong, which has resulted in some VMware customers who want to experiment with public cloud services to do so at competitors such as Amazon Web Services and Rackspace. "This is a basic offering that doesn't really have any bells and whistles, but is a reasonable way to get the 'feel' of a VMware cloud," she says, noting that it's not meant to be a formal proof-of-concept evaluation tool.

Rumors have circulated in recent weeks that VMware will be releasing its own infrastructure-as-a-service offering, as opposed to the vCloud network of service providers the company currently works with. Andrews, the VMware spokesperson, says he couldn't comment on speculation, but says VMware will "continue to invest in our service provider ecosystem," noting that VMware is a "partner-led company." VMware's chief, Paul Maritz, is slated to step down from his role as president and CEO next month and he will be replaced by EMC President Pat Gelsinger.

Rackspace, meanwhile, is doubling down on the company's investment in OpenStack, including recently releasing a product fully powered by OpenStack, which is the largest OpenStack-powered public cloud deployment, Leong says. Rackspace's free private cloud software, code-named "Alamo," includes a Ubuntu operating system running a KVM hypervisor. The private cloud software can be deployed in a customer's own data center, in a Rackspace data center, or in a colocation facility, and Rackspace private cloud guru Jim Curry says the announcement is meant to encourage hybrid cloud deployments that would allow customers to have a private cloud that connects in with the company's OpenStack-powered public cloud.

"We believe that the majority of our customers and cloud users will be running hybrid cloud environments for a long time," Curry says. This move could be a first step for organizations in that direction.

Network World staff writer Brandon Butler covers cloud computing and social collaboration. He can be reached at [email protected] and found on Twitter at @BButlerNWW.